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GramAmp 1 & 2 - phono preamps

[Italian version]

Product: GramAmp 1 & 2 phono pre-amps
Manufacturer: Graham Slee Projects - UK
Cost: GramAmp 1 - 59 UKP, GramAmp 2 - 89 UKP
Reviewer: Geoff Husband
Reviewed: February 2001

[Gram 1 & 2 preamps]

Authors note...

This review is heavily biased by the writers belief that anyone who does not possess a record player is MISSING OUT...

Introduction

One of the effects of the seemingly unstoppable progress of CD is that an increasing number of amps at all price points are sold as 'line-only' amps - i.e. they don't have a phono stage. At first this might seem bad news all round, but it has had unexpected consequences.
First it's meant that if you've just spent 150 on a budget integrated to play your CD's through, no money has been spent on engineering a phono stage. I also suspect that most manufacturers that do include a phono stage make it as cheap as they can, after all few reviewers will use the phono stage anyway. But the big plus point is that the number of off-board phono stages available, especially at the budget end of the market, has increased dramatically. With few exceptions these are going to be superior to the usual on-board item and allow easy upgrades. Some of these stages have come from big manufacturers like NAD, Rotel and QED, the subject of this test has come from a small specialist manufacturer - Graham Slee Projects.

Why a phono stage?

If you've ever tried to play a turntable through a line input you'll find the sound, apart from being very quiet, is tinny in the extreme. The reason for this is down to the limitation of the medium itself. Firstly a cartridge generates an electrical signal by moving a coil in a magnetic field or a magnet in a coil (Moving Coil MC and Moving Magnet MM respectively). The problem is that in order for the stylus/cantilever/generator to trace tiny groove variations it needs to move very fast and therefore be light as possible. Small, light magnets and coils mean only a very small current is generated - hence the need for an amplifier before a pre-amp in order to get the output up to line level.
Then of course there's the problem of the grooves themselves. As their shape is directly linked to the sound, big bass notes require big groove excursions. In order to get decent bass the grooves would have to be so big you wouldn't be able to get enough on the disc to allow for a half hours music. The answer is to record using a signal which has had all the low frequencies rolled right off. The phono stage then has a circuit that boosts bass frequencies by the same amount resulting in a flat frequency response. If every manufacturer used a different correction curve you'd need a different phono stage for each record label, but thankfully early in the microgroove record's history everyone agreed on a standard replay curve - the RIAA curve - simple. Well not actually. To amplify such tiny currents and apply the correct correction is no easy task, to do it properly takes care.

Which brings us to the two phono stages tested here, the GramAmp 1 & 2.

One thing I forgot - the RIAA curve is backed by another optional standard, the IEC warp filter. This rolls off the bass resulting in the response being 3 dbl down at 20 Hz and falling rapidly below. The reason is that otherwise record warps will cause a speakers cones to flap in and out particularly with ported speakers. The main problem with this is that it draws a lot of power from the amp which is unrelated to the music. In the days of weedy valve amps such a filter was obligatory, now with cheap tranny amp watts it's much less of a problem. The Gram 1 has such a filter to help budget amps and damp uncontrolled bass in cheap speakers, the Gram 2 runs without it.

Construction

No money has been wasted on fancy casework. Both are in identical plastic boxes. That said, the high gloss plastic finish has more than a hint of 'piano black' which is so fashionable today if you did want to show them off. Failing that, they are easy to hide. Power is provided by a plug in wall supply, but the raw DC it provides is regulated properly inside the stages themselves.

After this regulation in both 'Grams' is an NE5532 (AN version) op amp, chosen for its noise performance and ability to drive the RIAA network without breaking sweat. Here I'm getting into deep water technically (for me) but the manufacturer points out to special care taken with the coupling and input capacitors. The input coupling capacitors being calculated from the amps input 'looking' at the cartridge rather than the other way round as most manufacturers do. Thus (it is claimed) "the cartridge impedence is always in full control of the amp at low frequencies which also helps reduce hum". I can confirm the latter as both stages are very quiet. The RIAA network is an active type in the negative feedback loop. Apart from the IEC warp filter the main differences between the 1 and 2 is that the 2 uses Polypropylene capacitors, much faster than an amps slew rate - the 1 is more limited.

Round the back you'll see four phono sockets, two in/two out, gold plated on the GramAmp 2, a socket for the power supply and an earth post - and that's it. Oh and you are supplied with a phono lead to get you up and running. This is as cheap as you can buy and seriously slugs the performance. Graham Slee will sell you a better cable and this should be a must have for all but the most basic system or shallowest pockets.

Input sensitivity is 3mV which should suit all MM and high output MC's with input impedence at 47k and output is 250mV fine for pre-amps with gain but too low for passives unless the power amp is hugely sensitive. Graham Slee hasn't included a low output MC stage because he felt it couldn't be done properly at the price - a head amp to allow the Grams to be used with such cartridges will be available very soon.

Sound

The GramAmp 1 is aimed at the budget end of the market, something to hang on to a entry level - mid priced integrated amp. So being of fair mind I immediately wired it into a 6000 front end and 1500 pre-amp. As the Grams are MM only I used the Dynavector step-up with the XV-1, a combination costing about 50 times the Grams cost (just to put things in to perspective...). Before anyone moans about how mad this is let me say that it is the combination I know best, and that using such a 'microscope' will show ultimately what the qualities of the stage are.

So unplugging the wires from the Audion pre's superb all-valve stage brought the expected down grade. So what's the difference between a 'high-end' stage and the Gram 1? Well first the soundstage. It's much narrower, bound by the speakers, and shows little depth. Little acoustic clues as to the venue were lost, as was the space around the instruments that the Audion did so well. The power of the Audion was missing and bass through the IPL's attenuated somewhat, partly due to the IEC filter. There was a slightly 'clanky' feel as well. But all that said these are sins of omission not faults.
The overall effect was not unlike putting a mid price CD player into the system which considering it's intended market, those with a mainly CD collection, is probably no bad thing. Detail was there as was a good sense of speed and timing. For what is a beer money stage there was a lack of grain or spit, all in all it was quite pleasant to sit in front of.

The GramAmp 2 was something else... Given the lack of the IEC warp filter and other changes, I had expected it to sound a little different. What I didn't expect was for it to soundstage like a four-figure pre. This is the hardest thing for a phono stage to do. For it to come off the stage must faithfully preserve the information on the disc, including keeping a firm grip on phase. The Gram 2 was fully a match for the Audion in this respect.
Swapping to the Korato pre, which I strongly suspect is even better than the Audion, the Korato held on to a small lead in width and gave a slightly deeper soundstage. But though the difference was noticeble in an A/B I'm not sure I could have identified which was playing if I just walked into the room. And the Gram 2 gave nothing away in detail. It just lacked a little of the power and glory of the 'hi-end' stages, but at a tiny fraction of the cost this was a stonking performance. Putting a 90 phono amp into a 10000+ system might seem madness but in the context of my system it was a combination that worked well. Yes both the Korato and Audion were better but certainly I could live with the result.

Getting into the real world I trotted off to my Father-in-Laws house and tried both stages in his system. He has a good vinyl front end (A&R Legend, RB250, V-15) and an A&R integrated from a time when most people used vinyl (i.e. a cut above current built-in stages), and a pair of similar IPL speakers to my own - personal recommendation:-) This system is warm and friendly, a nice easy listen. Swapping around phono stages showed the Gram 1 to be just that bit more detailed and fast than the on-board stage, not a huge difference but probably worth the 60 if you were looking to upgrade the amp. The Gram 2 was that bit better again, a bit more powerful sounding, but it's better soundstaging wasn't on display. Both produced nicer noises than the budget Technics CD player...

Moans

At the price I can't really criticise. My only advice would be that unless price is absolutely critical go for the GramAmp 2. For the extra 30 pounds you get a big upgrade on all but the very best built in stages and something which will cope with a long upgrade path for when you get hooked (you will...).

Conclusion

If you have no record player ask yourself why not? A 100 pound turntable like the Project 'Debut' or a second hand Rega 2/3 plus one of the GramAmps and a decent cable will cost you 200. Then you have something that will last for years and years and give you access to the huge amount of cheap vinyl on the second hand market. Who knows what may happen? When I tell friends I've still got a record player I get all sorts of records given to me as people clear their loft. Maybe you've got a 100 records in a box in the loft (1500 to replace with CD's...), once loved, now neglected. Once you're hooked you'll be trawling the car boot sales with me and buying all Santana's albums (with those lovely gatefold sleeves) for the price of the 'Best Of' CD.
Either GramAmp with such a turntable will give a budget CD player a run for it's money when it comes to what's important in music - you may even learn to love the crackles:-). But the bottom line is that the GramAmp 2 is better than this, give it the ancillaries to let it spread it's wings and you'll see why 50 years down the line it is the microgroove record that remains the absolute reference for domestic sound reproduction.

Sale or Return

Graham Slee Projects is yet another company selling direct through the net using a very neat and simple site - and hooray! It's sale or return, no quibbles. You've got nothing to loose...

STOP PRESS!

Two things. First a GramAmp78 is now available for all of you who have emailed me about 78's in the past... Secondly Graham Slee is now marketing a fine vinyl playing system consisting of a GramAmp phono stage, a cable, one of the Moth Alamo turntables (made by Rega, and very similar to a Rega 2/3) and a Goldring MM cartridge - everything you need to become a vinyl nut.
This little lot, a 'Gram Pack', will cost under 300, much the same as a budget CD player and I suspect give at least comparable quality - the turntable and Gram 1 being well up to future upgrades of cartridge and amp. So next time you think of upgrading your entry level CD player you have to ask yourself "why not try the vinyl option instead?" - you may never look back.

NB. It has been pointed out to me that the 'goldmine' of cheap vinyl is not available in all countries - you have my deepest sympathy...

systems used

  • Vinyl: Michell Orbe SME IV/Dynavector XV-1
  • CD-players: Micromega Solo.
  • preamp: Audion Premier2, Korato KVP 10.
  • power amp: Audion ETPP EL34 Monoblocks. Korato KTA 100.
  • Cables: FFRC, LAB47 and Cabasse speaker cables. DIY silver interconnects.
  • Speakers: IPLS3mtl's, Cabasse Sloops, IPLM3's.

    Test records used... - Killers

Copyright 2001 Geoff Husband - http://www.tnt-audio.com

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